What happened there?

Somehow overnight, I got 80 new points from votes, but somehow my net reputation went down 133 points without any of my other questions or answers getting any down votes. I have no idea how that happened, but I don’t like it.

Update: It turns out that Jeff Atwood decided to implement some “fraud detection” and removed what he thought were “suspicious” upvotes. I should consider myself lucky – Konrad, who had the second most points on the system, lost 6,000 points and Daok, who was pretty high up in spite of the fact that English is obviously not his first language, lost 5,000.